An ankou is a terrifying fey creature of the First World that serves the nobles of that realm. As fey creatures cannot truly die in the First World, the ankous act as torturers bar-none, trained to make their victims wish for the release of true death.
An ankou resembles a horrific, skeletal, emaciated creature cloaked in darkness, with a flaming glow visible in its chest, shimmering black wings, sharp talons, and yellow eyes radiating malice. Usually, ankous prefer blinding their foes with darkness to letting themselves be seen. A typical ankou measures ten feet tall, eight feet across, and weighs less than 100 pounds.
An ankou's tail and wings can inflict particularly vicious wounds, described by victims as feeling like little shards cutting their way under their skin, which sometimes shimmer as if from residual moonlight. Some victims can die of exsanguination from what appears to be a mere scratch.
An ankou can create lesser copies of itself from shadow and wrath, blocking the way of victims, and shredding them with multiple slashes from the same claw. These copies share one mind with the original ankou, vanish when it is destroyed or unable to maintain them, and can only be blocked by an Eldest.
An ankou sleeps in a cocoon in the darkest corners of the First World when idle. The mere threat of an ankou is enough to deter most enemies, so they are rarely actually called to service. Against a hated foe, an ankou might be tasked to murder its target, wait for it to reform from its connection to the First World, and then kill it again multiple times.
In the Eldest's courts, ankous usually lurk and serve as a purely psychological threat, as the Eldest themselves are powerful enough to get rid of those that displease them. They typically execute their assassinations without inherent malice, which can be incomprehensibly terrifying to Material Plane dwellers to whom death is the end, instead of a mere annoyance like on the First World.
An ankou whose master is permanently destroyed will wander at will. Free ankous are even more murderous and easy to offend than employed ones, but less concerned with repeated murders. They prefer to be left alone in abandoned, morbid places, and those who bring light or music into their demesnes will be briefly tortured and killed. Because of this, fey pranksters who discover their lairs often try to taunt them, eventually forcing the ankou to relocate.
At the beginning of their race, the ankous all served one master: the Eldest Count Ranalc. After he disappeared, most of them left, either to roam free or to serve other Eldest, but a few loyalists stay in his old realm, Nighthold, to keep it safe and prepare for his return. Seeking to fulfil some unknown order in the past, they have killed many believed to have had a hand in his disappearance or know of his whereabouts. Some of them have come to Golarion, believing that their liege might have left evidence of his passage on the planet, but no ankou can say whether this is true or not.
- Ankou (real-world mythological creature) on Wikipedia